This invention relates to the cooling of water stored in a reservoir as the water is dispensed and more particularly to a cooling chamber for use with a room temperature water storage reservoir from which cooled water is to be dispensed and cooled.
A conventional chiller or cooler used for dispensing liquids such as a cooler/dispenser used for bottled water utilizes refrigeration equipment including a compressor unless the liquid is within a reservoir surrounded by ice or a refrigerant or other heat transfer medium. Examples, of the latter are illustrated in Pique U.S. Pat. No. 2,506,840; Olson U.S. Pat. No. 2,821,844; Geisler U.S. Pat. No. 3,270,520 and Bonimi U.S. Pat. No. 4,238,053; while examples of the former are illustrated in Natter U.S. Pat. No. 3,462,970 and Schroeder U.S. Pat. No. 3,892,335; while Radino U.S. Pat. No. 5,079,927 illustrates a hybrid combination of these. In Moren U.S. Pat. No. 5,544,489 there is disclosed a thermoelectric device having a probe that extends into water within a receptacle to cool the liquid, the thermoelectric device being one which responds to a direct current input to provide one side relatively cooled and one side relatively heated.
One problem that has been recognized with combination chiller-dispensers having a water storage reservoir is that the stored water may easily be contaminated with air-borne bacterial. It has been found that a substantial percentage of such units have bacteria levels above that permitted by governmental regulation. In such storage reservoirs and also in the bottled water used with chilling dispensers air must enter and displace the water to permit the water to exit. Thus, even with apparatus that purifies water, such as that disclosed in Greene et al U.S. Pat. No. 5,662,779, when the water is dispensed through a cooling dispenser, the water may become contaminated when the water is dispensed. As the air enters so does bacteria, mold and viruses carried by the air. These organisms may grow and multiply in the stored water resulting in potential sources of disease. If the water bottle or storage tank into which the air may enter could be eliminated, the growth of bacteria from air-borne sources may be greatly reduced.
This problem was recognized in my aforesaid U.S. patent application Ser. No. 09/085,672 where it was proposed to have chilling and dispensing apparatus including a thermally conductive probe within a cooling chamber in heat conducting contact with the cold surface of a thermoelectric device which produces a cold first surface and a hot second surface, the probe being immersed in a liquid heat transfer medium, preferably water, in which a coil of tubing is disposed about the probe. The coil has an inlet end and an outlet end and thus water fed to the coil may be cooled and dispensed.
As described in my aforesaid patent application, the heat transfer medium around the probe becomes supercooled and, if it is water, forms an ice ball. If the cooling chamber is small so that there is a small amount of cooling water, the ice ball may form quickly. As the ice ball forms, it compresses the air within the cooling chamber and raises the pressure unless a lid on the dispenser housing is opened. However, in that case bacteria laden air may enter, and after a time, the cooling water within the tank begins to have an unpleasant moldy odor.